While I'd like to shoot 34g slugs, I personally feel like the 600mm is most comfortable shooting roughly 30g or less slugs (with the exception of Altaros ATP Kings). I've found these to work well with an OEM Panthera.
I do agree the 30gr work pretty darn good, but the 34gr run flatter and fight the wind better. Currently running the reg @ 162 bar and micro @ 3 for 975 fps. 10 to 15 mph winds is pretty much standard where I'm at. Early mornings and just before sundown is the only times when the wind is just a light breeze.
I have a 700 mm panthera so not exactly what you asked for but my 700 I run the 34 gr. H&N at 1018 fps with the reg on 150 bar. I cant remember my macro micro wheel settings off the top of my head but it doesnt really matter since its a 700mm. I just did my impact m3 700mm .22 with the H&N 34 gr. and its shooting very good at 965 fps with that slug. My panthera didnt seem to shoot as consistent at the 950 ish fps mark like the impact does.
The only negative side I see running the 34gr is efficiency. I'm getting 33 shots. I may be able to squeeze out a few more with more tuning. It's amazing what that extra 4" of barrel gets you
Yes. I knew the way I would be using this panthera would be setting up on a ground squirrel field or rock chucks and just sniping them. No walking thru the woods with it so I went for the 700mm. I have short compact rifles for woods walking or tight quarters.
Not setting any records here, but it has potential. I definitely pulled a few along with the winds. 50 yards. I refilled at shot #9. All 5 shot groups, except the center target. Was on the reg there.